package cn.tedu.sp06.fallback;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

@Component
public class OrderFB implements FallbackProvider {

    //针对哪个服务应用当前降级类
    //返回服务id
    //   item-service   - 只针对商品降级
    //   *              - 对所有服务降级
    //   null           - 对所有服务降级
    @Override
    public String getRoute() {
        return "order-service";
    }

    //返回的降级响应,封装在response对象中
    //根据自己应用的需求,可以返回任意的响应数据
    //   - 错误提示
    //   - 缓存数据
    //   - 执行业务运算返回结果
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;       //500, internal error
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();  //500
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase(); //internal error
            }

            @Override
            public void close() {
                //ByteArrayInputStream流是内存数组的流,不占用底层系统资源
                //不需要close()释放资源
            }

            @Override
            public InputStream getBody() throws IOException {
                //JsonResult     -{code:500,msg:系统服务故障,data:null}
                String json = JsonResult.err().code(500).msg("系统服务故障").toString();
                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders h = new HttpHeaders();
                h.add("Content-Type", "application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
